Issue integrating Avatax for Sage 50:

First, we entered a negative invoice into Sage 50 (because a credit memo does not work for invoices that have been paid). The reason for the negative invoice is for a customer refund. 

We then run "Avatax for Sage 50" to add the negative tax. Avatax runs and computes the negative tax based on the "Ship To" address on the negative invoice. 

When you open the AR report in Sage you can see that the negative invoice calculated the tax as a positive amount. For example. ($100 negative invoice, $8 negative tax shows up as $92 instead of $108)

However, when you open the invoice and click save (without making any changes), the tax is corrected to be a negative amount and the invoice total is updated to $108 (in the example above).

Very frustrating because Avalara is saying that it is a Sage issue, and Sage is saying it is a 3rd party issue. Even though the product was purchased with the assumption that they worked together. Have already spent hours trying to get help from both sides on the issue and still no resolution.